Types of Barley Malts
Malt influences the flavor of beer more than any other ingredient. The malt types selected for brewing will determine the final color, flavor, mouth feel, body, and aroma. Depending on the style of beer desired and the type of malt, it takes from 15 to 17 kg (33–37lbs) of malt to produce a hectoliter of beer. There is no universal system used in classifying malts since maltsters categorize and market their products differently. However, most often malts are classified either as base malts, specialty malts (highly-kilned malts), caramel malts, and roasted malts. Base malts usually account for a large percentage of the total grain bill, while specialty malts account for a much smaller proportion of the total grist bill. The only exception is wheat malt, which can make up to 100 percent of the total grain bill in brewing wheat beers.
Base malts provide most of the enzymatic (diastatic) power to convert starches into fermentable sugars. The ability of malt enzymes to convert starch is called the diastatic power (DP), measured in the United States and the United Kingdom in degrees Lintner (°L). The base malts provide the highest extract potential. Variations of base malt are produced by changing the degree of modification and the temperature and duration of kilning. Because base malt retains amylolytic activity, it is typically used at 60 to 100 percent of the grain bill.
Pilsner malt or lager malt is the standard malt type used for most lager production (Figure 2.3). These malts are produced to retain maximum enzyme activity and to preserve certain sulfur-based flavor precursors characteristic of light-colored lagers. They produce less color and flavor than standard base malts and are very useful in producing beers in which other flavors and aromas are to be achieved. Traditionally, they are less modified than pale ale malt, as indicated by the harder kernels.
Pale Ale Malt
Pale ale malt has a subtle malty and biscuit profile especially suitable to British ales (Figure 2.4). Pale ale malt is traditionally more fully modified, with a lower protein content and more easily accessible starch than Pilsner malt. Pale ale malt is usually kilned at high temperatures, which gives it a darker color and more malt character than Pilsner malt. They have an evident, but not excessively pronounced malty flavor, with notes of biscuit or toast.
Mild Ale Malt
Mild ale malt is kilned at a higher temperature than pale ale malt but still has enough diastatic power to be used as a base malt or as a substitute for a portion of the base malt.
Vienna malt is very close to pale ale malt but is kilned at a higher temperature to emphasize the production of melanoidins that are responsible for differing flavors and aromas. It gives beer a richer, maltier flavor, some degree of fullness, and a golden color. In contrast to most crystal malts, use of Vienna malt results in a beer with a refreshing, dry finish.
Munich malt, like Vienna malt, is kilned at high temperatures to emphasize the production of melanoidins (Figure 2.5). It gives an amber color to the beer; however, its most important contribution is a nutty, rich malty aroma and flavor malty, sometimes bordering on toasty depending on how highly it was kilned.
Specialty malts often undergo the same malting processes as base malts but have experienced treatments (typically heat and moisture conditions) designed to produce different flavor, color and functionality outcomes. The specialty malts are designed to contribute a unique characteristic to beer, such as color, flavor, mid-sized proteins for foam improvement, body, or other accentuating characteristics.
This malt style actually came about as an innovative way for German brewers to have control over their mash pH while also adhering to the purity laws of Reinheitsgebot, which states that beer must only be made with malt, water, hops and yeast—so no additives like phosphoric or lactic acid in the mash. Proper mash pH (5.4 to 5.6) helps assure the enzymatic performance on which the brewer relies to break down gums, proteins, and starches.
Dextrin malt is a type of malted barley used in brewing to increase dextrins in wort and finished beer (Figure 2.6). Dextrins are long-chain sugars that are unfermentable by brewer’s yeast. Dextrin malt is the lightest in color, are high in unfermentables, and contribute to the beer’s body without affecting color. Dextrin malts are similar to caramel malts but have been dried at a lower temperature to prevent the formation of color and flavor compounds.
Melanoidin is a kilned specialty malt with an intense malt aroma and unique brewing characteristics. It has a high degree of modification of both proteins and starches, excellent friability, low beta-glucan values, and high acidity.
Smoked malt is made by drying the malt wholly or partially using the direct combustion gases of a wood fire, which imparts an intense smoky flavor. Traditional versions (associated with the city of Bamberg, located in Franconia, Germany) use beechwood as the fuel source. Other special woods (such as cherry and alder) are used in other areas of the world.
Brewers are often confused by the terms caramel and crystal malt and are sometimes uncertain as to whether these are basically the same and can be used interchangeably, or whether they completely different. Partly this comes from the fact that crystal and caramel malts come in a range of different colors, and that individual products from one maltster may not be identical to those from another producer. They are in fact proprietary products and are often given proprietary names, which only serve to increase the confusion. Many maltsters producing caramel-type malts in a roaster use the term “crystal” to designate them as roaster produced.
Caramel malts are conventionally produced from green malts using a process called kilning. These malts are treated at much lower temperatures than that of crystal malts as well as more variable temperatures due to a larger surface area. Due to the location of grain in the kiln bed and the temperature of the kiln this creates a mixture of malts, some of it with the glassy, caramelized center typical of caramel malt, but some with the malty, mealy character typical of high dried malt.
Crystal malts are conventionally produced from green malts using a process called roasting (Figure 2.7). Crystal malts fall under the category of caramel malts. Crystal malt is malt that has undergone a typical steeping and germination period followed by an additional moist heating procedure. These malts are not dried in a kiln but are roasted, often in drums at a very high temperature. In the production of crystal-type caramel malt, the drum is rotated and slowly heated to bring the grain up to starch conversion temperature, roughly 65.6 degrees C (150°F), just as is done in the mashing process in the brewery (Liscomb et al., 2017).
Roasted malts require a drum roaster because of the very high temperatures involved in the process. The drum can be loaded with green malt, finished malt, or even unmalted grains depending on the desired final product. Roasted malts include amber, black, brown, and malt.
Amber malt is a traditional British malt, well described by its name that is produced by gently roasting mild ale malt (Figure 2.8). It is used in a few amber and dark ales and is generally used to produce premium bottled ales. In its original form it was a classic porter ingredient in the late 18th and early 19th centuries, when many porter grist formulations consisted of equal parts pale, amber, and brown malts.
Biscuit malt is actually a type of roasted malt, but is roasted to a very light degree at around 25 to 30 degrees Lovibond. Biscuit malt has a flavor described as warm bread crust, biscuit, and earthy.
Brown malt is sometimes kilned over a hardwood fire, which imparts a smoky flavor to the beer. Brown malt will add sweetness, some biscuity character, some toasted notes, caramel, toffee, and particularly licorice flavors.
Making black malt involves roasting the malted barley at temperatures so high that they drive off all of the aromatics (malt flavor). There are no enzymes in black malt. It contributes acrid flavors and an astringent mouth feel to styles like stout ale.
Chocolate malt is not roasted quite as long as black malt; consequently, it is lighter in color—darker brown—and retains some of the aromatics and flavor of malt’s sweetness (Figure 2.9). The mild burnt flavor it carries pairs well with the rich coffee and chocolate notes that are developed as Maillard products when it is roasted. There are no enzymes in chocolate malt.
Roasted barley is unmalted barley roasted at high temperatures (Figure 2.10). Roasted barley is not black in appearance; it is rather a rich, dark brown. It has an assertive, roasted flavor, similar to roasted coffee beans, with a sharp, acrid after-palate, and is especially used in the making of dry stouts and porters. It contributes significantly to the color of the beer, enhances head production and stabilization, and whitens the head on the beer.
Other Malted Grains
Wheat malt, for obvious reasons, is essential in making wheat beers making up to 100 percent of the grists, including the German Weissbier (white beer) and Weizenbier (wheat beer). Wheat is also used in malt-based beers (3–10%) because its protein gives the beer a fuller mouthfeel and enhanced beer head stability. Other benefits claimed are improved beer clarity and palate fullness (Briggs et al., 2004). On the down side, wheat malt contains considerably more protein than barley malt, often 13 to 18 percent, and consists primarily of glutens that can result in beer haze.
Rye malt, like wheat malt, is husk less. It yields less extract than the other malts previously discussed and is slightly darker than barley or wheat malt.
Malt extracts are made by griding the malt, mashing it, with or without adjuncts and supplementary enzymes, and then separating the wort. Many different types of malt extracts can be produced depending on the malt, the mashing regime, and the evaporation conditions used. Typically hopped or unhopped malt extracts are used by home brewers and small-brewers because they lack the facilities for milling the malt, mashing, and wort separation.
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